This invention relates to pollution control systems and more particularly to particulate and gas collection systems for electric arc furnaces.
Electric arc furnaces are commonly employed in a variety of metallurgical operations, such as the melting of scrap metal and in the refining of iron and steel. Such electric arc furnaces generally include a furnace body and a removable roof through which the electrodes extend. Periodically during a furnace operation, the roof and electrodes are elevated and swung away from the furnace body to permit charging with scrap, hot metal, pig iron or other furnace charge. In addition, when the treatment of each batch of metal in the furnace is completed, the furnace is tapped and the molten metal collected in a ladle located along one side of the furnace. During the charging and tapping operations, large amounts of polluting gases and particulate matter are released into the surrounding environment. Additional pollutants are also released from the furnace through various openings during the furnace metallurgical operations.
One type of prior art systems for collecting gaseous and particulate pollutants from electric arc furnaces includes a furnace enclosure having collection ducts located at critical positions therein. Examples of such prior art furnace enclosures are disclosed in U.S. Pat. Nos. 4,088,824 and 4,477,910. Each of these patents discloses a first gas and particulate collector adjacent the upper end of the enclosure and a second collector adjacent the tapping ladle position.
Another example of a prior art pollution control system for electric arc furnaces is disclosed in U.S. Pat. No. 4,410,166 which shows an arc furnace enclosure having a gas collector which is movable to permit furnace charging.
A further expedient employed in the prior art for collecting pollutants and arc furnace enclosures involves blowers for directing gases and particulate material toward prepositioned collectors.
Such prior art gas collecting systems have generally been a compromise with respect to various furnace sizes, operating sequences and pollution sources.